Question detail
What happens to the position of equilibrium when the pressure is increased in a reaction involving gaseous reactants and products?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Chemical equilibria, Le Chatelier's principle and Kc
Question
- A. The equilibrium shifts to the side with fewer moles of gas
- B. The equilibrium shifts to the side with more moles of gas
- C. The equilibrium remains unchanged
- D. The reaction rate decreases
Answer
The equilibrium shifts to the side with fewer moles of gas
Explanation
The correct option is The equilibrium shifts to the side with fewer moles of gas. The equilibrium shifts to the side with fewer moles of gas is the best answer because it directly supports the AQA A-Level Chemistry objective to use Le Chatelier's principle to predict the effect of pressure changes. This reasoning is anchored to Equilibrium and Le Chatelier's principle in Chemical equilibria, Le Chatelier's principle and Kc, and it separates Le Chatelier from similar A-Level ideas rather than relying on a vague recall statement. Other options are weaker if they use the wrong evidence, calculation, mechanism, observation, unit, or conclusion for this subtopic.
Common mistake
Pressure Change Misunderstanding
Students often think that increasing pressure will always shift the equilibrium to the right, regardless of the reaction.
To fix this, remember that increasing pressure shifts the equilibrium towards the side with fewer moles of gas. Always analyze the balanced equation to determine the effect of pressure changes.
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